OUTLINE:

“in vain”
to Paul, Christ’s resurrection was fundamental to the faith; he was saying that if Christ wasn’t resurrected, then our faith is worthless

Jn 8:56
“Your father Abraham rejoiced to see My day, and he saw it and was glad.”

A Confident Conclusion From Gen 22:12
"Dear God, now I know that You love me, because You have not withheld your Son, your only Son, from me."

Ps 16:10
For You will not abandon my soul to Sheol;
Nor will You allow Your Holy One to undergo decay.

Jonah 1:17
And the Lord appointed a great fish to swallow Jonah, and Jonah was in the stomach of the fish three days and three nights.

Jn 8:24
“Therefore I said to you that you will die in your sins; for unless you believe that I am He, you will die in your sins.”

1Co 15:17
If this (errant) logic were true, we’re in no better condition, positionally than the unbelieving Jews that crucified Jesus!!!

“in this life only”
assuming there is no resurrection, we’d have nothing to look forward to (even Jesus would still be in the grave, not seated at the right hand of the Father in Heaven)

John 12:23-24
And Jesus answered them, saying, "The hour has come for the Son of Man to be glorified.  "Truly, truly, I say to you, unless a grain of wheat falls into the earth and dies, it remains alone; but if it dies, it bears much fruit.

1 Tim 4:10
For it is for this we labor and strive, because we have fixed our hope on the living God, who is the Savior of all men, especially of believers.